import { readLines } from "https://deno.land/std@0.177.1/io/read_lines.ts";

async function Part1() {
    const file = await Deno.open("./Day7/input.txt");
    const lines = readLines(file);
    let line: string = (await lines.next()).value;

    const positions = (line.split(","))
        .map(x => +x)
        .sort((a,b) => a - b)
        .map(x => +x);

    let optimalPosition = 0;

    if (positions.length % 2 == 1) {
        optimalPosition = positions[ (positions.length -1) / 2];
    } else {
        optimalPosition = positions[positions.length / 2];
    }

    const cost = positions
        .map(x => Math.abs(x - optimalPosition))
        .reduce((a,x) => a + x);

    return cost;
}

async function Part2() {
    const file = await Deno.open("./Day7/input.txt");
    const lines = readLines(file);
    let line: string = (await lines.next()).value;

    const positions = (line.split(","))
        .map(x => +x);

    const mean = positions.reduce((a,x) => a + x) / positions.length;
    const optimalFloor = Math.floor(mean);
    const optimalCeil = Math.ceil(mean);

    const fuel = (x : number) => x * (x + 1) / 2;

    const FuelCostFloor = positions
        .map(x => fuel(Math.abs(x-optimalFloor)))
        .reduce((a,x) => a + x);

    const FuelCostCeil = positions
        .map(x => fuel(Math.abs(x-optimalCeil)))
        .reduce((a,x) => a + x);

    const cost = Math.min(FuelCostFloor,FuelCostCeil);

    return cost;
}

console.log("Part1: " + await Part1());
console.log("Part1: " + await Part2());